The excellent Human Transit blog has a detailed discussion of Muni’s new all door boarding policy, the first in North America. It definitely will help riders get where they are faster, with fewer delays, which is why we have advocated it for the better part of a decade.
One important point that the author makes is around fare evasion:
“On all-door boarding, you as a passenger can’t tell whether others have paid their fares, and when you see someone a guy who looks shady to you (whatever that means to you in terms of race, class or behavior cues) jumping on the back, you’ll now have to accept that what he’s doing is now perfectly legal and that you have to assume that he has proof of payment. It’s up to a fare inspector, not you, to verify that.”
So long as SFMTA maintains a sufficient level of fare inspection that riders really do have a reasonable expectation of being checked, this should not be a major problem – though it is very important that inspectors show up at times when evasion has been a problem in the past (e.g. after school hours, evening rush on Market Street). This will also help address riders’ security concerns.